Some ideas are just too clever to die. Like Vehicle-to-Grid (V2G) — the notion that your electric car can act as a home battery. Park it at home, plug it in, and when the sun goes down or prices spike, your car sells energy back to the grid. It’s green, it’s clever, and it feels like you’re gaming the system.
Home batteries are expensive. EVs are becoming standard. So the idea of getting a ‘free’ home battery with your car is irresistible – if you don’t look too closely. Especially if you imagine selling electricity at $10 per kWh while your neighbour’s paying 40c per kWh to charge their Tesla.
It feels like financial judo.
But in reality, it’s all hassle, cost, and fiddliness — in exchange for pocket change and an illusion of control.
V2G Is A Complicated Detour
First: batteries are getting cheap. Battery cells are already under $100 per kWh. Home battery systems are still stubbornly expensive, yes. But history tells us that won’t last. Just like solar panels, prices will fall and home batteries will be everywhere.
Second: bidirectional EV chargers will always be more expensive than normal ones. More hardware, more complexity, more paperwork. You’ll deal with tougher installs, picky DNSPs, and call centres who barely understand how to spell ‘V2G’, let alone support it.
Third: it’s a ball-ache. A home battery is most useful when it’s always at home. Putting it in the car breaks that. You need the car? Bad luck — now your house can’t run off cheap energy. Car’s not plugged in? Back to buying from the grid. Got two cars? Welcome to charge juggling. Want your 17-year-old to remember to plug in every time they park? Good luck.
And all this for what? Maybe a few bucks on a good day?
People don’t want fiddly. They want simple. That’s why we pay more for products that just work. Like paying $20 a month for iCloud because plugging in your phone to sync it feels like admin.
As battery prices fall, the appeal of V2G will fade. Remember ten years ago when everyone was going to go off-grid in the suburbs to dodge a $1 daily connection fee? I got pilloried for saying no one actually wanted that hassle.
Even Elon Musk — whose recent track record makes Clive Palmer look focused – managed to get this one half-right. He said:
“If you unplug your car, your house goes dark.”
Not true. Your house just pulls expensive grid electricity instead – which is exactly what you were trying to avoid. But the real point? V2G is a pain.
Better Ways To Use Your EV Battery
That’s not to say EVs can’t help. Quite the opposite. When they’re parked and plugged in, they’re great at soaking up excess solar and wind. Smart charging during the middle of the day – that’s the easy win. No bi-directional hardware required.
And yes, V2L (Vehicle-to-Load) is genuinely useful. Great as an emergency power source during a blackout, making toast at a campsite, or running power tools on a remote worksite – as long as your car’s got the grunt (looking at you, BYD Shark).
But powering your house every night from your car? That’s when the wheels fall off.
Stop Spinning Your Wheels
One of the biggest problems with V2G isn’t just the complexity — it’s the distraction. It makes people wait. Wait to buy an EV. Wait to size up their solar. Wait for new home battery tech. All for a perfect solution that may never arrive.
But big bills are here now. The energy transition is already underway.
The tech that works is already on the shelf. V2G isn’t.
So don’t wait. Expand your solar. Add the battery. Get the EV.
Use what works — now.
About Finn Peacock
RSS - Posts
This is SUCH a good article Well said Finn!!!! Bravo! Best article that anyone has written ever on this industry!
It’s important to get the numbers right.
$100/kWh ? Great, I’ll buy 10,000 at that price. $1000/kWh is closer.
Michael, the cells ARE probably about that US$100 / kwh mark, last I saw 2024 info was US$115, but that’s likely gone down some more by now.
This is cells, not complete home battery package with BMS and all the surrounding support that the cells themselves need . . . a home (as in a nice cabinet), software, assembly / internal wiring, compliance costs.
That’s where the AU$1000 per kwh comes in, along with markups.
I’m surprised, Finn’s articles and comments are usually positive and forward looking. As Finn usually points out the technology can only improve, become simpler and cheaper.
As a retired couple our EV would be solar trickle charging most of the day, most days. It would then be be our home battery and our emergency back-up. I understand that wouldn’t work for everyone but what does? Am I missing something?
We have had a house battery since 2018 we live a bit out of town in an area that has bushfires. Plus a house protection sprinkler system run off water tanks and electric pump. Also installed 10kWh BYD LiFePO with a Selctronic inverter so if power goes off it switches to battery in 65ms.
We have used it a couple of times in blackouts and on one occasion were unaware of the blackout until a neighbour rang & asked how come our lights were on. Not paid for grid electricity since 2018 current power bill $217 in credit.
We also have had an EV for 4yrs, understand the point of your article. We may need the car at the same time we use our house battery.
Hi Terry,
How big is the pump you’re running. I’d love to see some details of your setup, it’s sounds a lot like my own.
Cheers
Two standard house electric pressure pumps one off our water tanks the other off our house dam.
Have tested with 5 agriculture sprinklers and works OK.
3 main sprinklers fixed for house coverage on house pump and two portable for unexpected fire direction on dam pump. So far not not used in actual fire in 25yrs, just testing seems good coverage.
Also have hose reel on house to cover gaps
Many years in Rural Fire Service and fought many bad fires. If real bad fire and there is time we will most likely evacuate, sprinklers are in case we are cut off.
Hi Terry,
That sounds pretty good. My limited experience in fighting the Pinery fire was that it was a weather event we were up against. Sprinklers on the house would need to be well up wind to actually offer coverage, such was the strength of the gale.
Two pumps is a load that shouldn’t be sneezed at but the Selectronic unit is in it’s element running things like that.
So let me get this straight — V2G is a dead end because it’s not perfect yet? By that logic, we should’ve scrapped solar panels in the ’90s because they weren’t cheap, efficient, or easy to install either. Technology matures — it’s not born in its final form like Athena from Zeus’s head. Sure, V2G isn’t ready for primetime everywhere, but calling time of death before the patient’s even out of triage seems a bit premature. Let’s not toss the baby out with the bidirectional charger just yet.
Why not wait to buy an ev when they are at least 30 percent more costly upfront than their ice equivalents. I’m waiting for realistic pricing and V2H. I don’t care about V2G as there is no way the government, the retailers and the suppliers are not going to screw us all over again there as they have with feed in tariffs , plus i have no intention of ever labouring my batteries to prop up a grid that is solar starved due to poor planning and base load starved due to climate extremist zealots who are happy to increase unsustainable government borrowing for their ideals at the expense of the next generation , l.e our children
Not to mention very few vehicles in the market support V2G, and the warranty implications from added battery cycles. People will keep asking until they get the answer they want to hear, thoughts and prayers to your comments section.
A 4000 cycle LIFEPo4 ev battery used for 1/4 of range per day theoretically could last 40 years. But time degradation brings it down to 15 – twenty years. Some studies show the light loads and charges On lithium batteries can help their lifespan. So its a use it or lose it anyway scenario so using traction battery for house loads which is at most 1/10C discharge isnt adversely affecting the traction battery.
Absolutely correct! When Tesla responded to why they don’t offer the answer (V2G or V2L) was simple the battery will normally just last longer than the EV about 15 years before needing to be repurposed or scraped. If you start charging discharging more often you will shorten its life. Next gen batteries with longer life will give you comfort but that’s not here amd nit for a few years yet.
They support V2L. So if you decide to hook up your V2L adapter to a HOEM and run part of your house from your car battery it’s fine, but V2G (or more.specifically V2H) isn’t?
Agree with most of that.
Since stumbling on household battery prices on Ali Baba (ex China) I have been babbling on about how cheap household batteries could get. Modular, virtually Plug and Play and $100 (US?) per kWh.
And I never saw the sense or need to run your house from your car. When I eventually buy an EV it will preferably have V2L.
But I disagree about Grid Defection. We have been running 99% off grid for three years now and it wouldn’t take much to convince me to go off grid once the SA PFiT ends. Looking at you AGL.
WA already have a service charge for consumers with electricity available that aren’t connected to grid. So get the daily charge regardless.
You can bet this will be introduced on east coast when too many of us disconnect.
Finn, for once I have to disagree with you. My car would spend plenty of time at home charging from my significant excess solar and could easily manage the “complexities” of making sure I had enough battery for use. I have no 17 yo boy to worry about nor anyone else. I also have other vehicles.
The benefit – a battery that would already be there and although mobile would be largely at home at the times needed to provide charge to grid.
I would also suggest that most people on this site would be capable of managing the minor complexities involved. And so far I have had very reliable electricity supply here so don’t really need a battery for support during blackouts. Although who knows what may happen in the future. Mind you, there would be no sense in spending significant money to upgrade an existing inverter or add extra equipment. However, I expect to add an extra solar system in the next couple of years.
Finn is against it because he doesn’t get a clip from selling an EV. He would prefer selling ‘battery installer vetting service’ to get commission from it. Make the best decision for your household not his business.
$35k Nissan Leaf with V2L V2G is the best bang for your buck.
Hi Padide,
You’re so far off the mark it’s funny but in the interests of transparency we’ll publish your insults.
We have followed V2G closely, Finn has interviewed the owner of the first domestic V2G owner in the country, I was there to see it first hand.
Nissan Leaf is a fine car but the V2G Wallbox Quasar is no longer manufactured & if you can get existing stock it’s $10,000 a pop without blackout capability.
https://www.solarquotes.com.au/blog/v2g-bidirectional-installation-mb2766/
I second your comment about the pain in the butt. I live off grid and going through being connected at the moment, mainly because it will be cheaper compared to buying batteries every 12 years, plus electronics. In support of your point, I supervise first year uni students to assess the costs over 25yrs of going off grid to bring on grid. Taking into account the initial connection cost for say a small rural block. I get them to add in a sensitivity cost for the pain in the butt for being off grid. This covers checking the battery levels most days, solar generation and cloud cover. Real numbers surprise a lot of people.
The V2G trying to save a few dollars is a bit like the new demand tariffs, you miss covering your demand for one day per month and you wasted the other 29days of the month trying to save $20.
Cheers
Hi Trevor,
I’ve always told people the grid is a no brainer if it’s available and defecting from it is lunacy.
Please; you simply must share with us the calculation you’re using to make sense of that.
People get irrational about disconnecting from “the bastards” who don’t pay properly for exported energy but they don’t appreciate the cost of a backup generator or the hassle of disposing of a freezer full of food.
Let us know 😉
Where I am (regional NSW) the daily service charge is now exceeding $2/day, approaching $800/year.
It’s not ever going down and will be $1k/year before long without consuming anything. There’s nothing grid-tied solar PV or battery (stationary or mobile) can do about that.
It is certainly making off-grid a more attractive proposition, particularly if the grid is mainly being used as a backup generator.
Hi Alex,
I hear what you’re saying but truly remote area power needs a system about 4 x larger to cope with low solar weeks… plus a generator.
Modest grid hybrid will work 95% of the time without needing to overengineer like true off grid.
Spot on Anthony, x4 is a lived-experience minimum. (My 27 kW of panels are good for one bachelor – would need more for wife & kids, I figure.) At 10% yield in heavy overcast, I still finish the day with batteries at 100%.
The 46.5 kWh of batteries are enough even when there’s a full household or two. (That’s not quite x4, but close.) Excess panels reduce battery requirements, even if facing south.
Double up the inverters for redundancy = 2 AC inverters + 2 battery inverters, then there’s still lights & icecream when one goes down.
But the generator only needs to be a cheap little Honda here, as 3.2 kW average input is x10 on idle consumption (LED lighting), with HWS & aircons off. A generator only needs to slowly catch up on baseload, as the batteries handle all peaks. (The tank holds 4 hrs of fuel, that’s auto-shutdown after 13 kWh of top-up – saves a walk to turn it off.) Mind you, haven’t started the generator in 14 months – should do it to purge the stale fuel.
Exercising the generator is a great idea Eric.
As an off grid electrician, the main purpose of a generator is to make my phone ring.
Trevor, in the 21st century, no-one has LA batteries any more, surely? LiFePO₄ has no fluid levels to check. The Jikong BMSs have 2A active balancers, so cells are top-balanced daily. Nerds can click the phone app to admire the shiny numbers, or check battery cycles for amusement. Others, blithely ignore. *Nothing* to do, until web monitoring falls over & needs a kick.
After 1st year, *zero* battery attention given. At 6,000 cycles, 20 yr calendar life comes first, at minimal replacement cost by then. Inverter replacement @ 10-15 yrs is likely a higher maintenance item.
46.5 kWh has been ample with 1 sunny day in 9, EV and all! 27 kW panels thumps the EV & HWS in sun, & a bare 10% in heavy overcast exceeds 2.3 kW HWS demand.
Design for off-grid, if going off-grid, I suggest: 65x420w panels, 12 kW AC inverters + 16 KVA inverter/chargers, ample MPPT for black start, does it here.
Backup generator not used here. A cheap 3 kW Honda exceeds average consumption, so suffices.
Finn, I can see both sides of your argument. I know what is missing.
The problem of the bi-directional charger & its cost is a big one, but I am wondering if there will be a cheap V2L adaptor that will allow that feature of the vehicle to be used in a V2G way. One issue with that I have not yet investigated is once the compliance issues are sorted because you are connecting a non approved vehicle as a grid supply, but also it would be nice to be able to revert to the vehicle charging without needing to physically intervene. I think this will be possible using switching in the charger. Home Assistant OCPP bi-directional control is already available now. I can see this as a peak load device to reduce peak loading.
Another issue is we are a tiny market in the world, & our compliance is very strict. This will mean any V2G will need an expensive approval process, including possible changes to the vehicle firmware. Low volume vehicle sellers are not going to bother.
Agree with you. For V2G to be a game changer the car needs to be regularly charging during the day and nearly always home in the afternoon/evening, which leaves it as niche for retirees and WFH’efs or the ‘retired engineer’ types who love to spend their spare time optimising their home energy system. At some point when workplace or away from home charging is pretty much universal and cheap it makes a lot more sense, but we are decades from that. In the meantime it feels like a complement to having a battery at home, not a replacement
FWIW in Australia (worldwide really) the ‘niche’ group is the Mon-Fri 9-5 worker. (I don’t think it changes the basic argument that V2G is unlikely to ever be popular due to the factors mentioned in the article)
About 35% of working age Australians don’t work (ie don’t need to, or they are raising kids, studying etc etc). 15% are retired. 5% are unemployed. That’s 55% right there.
Of those who do work, ~15-20% use public transport, ~30% WFH at least a day or two per week, ~20% do some form of shiftwork, and ~30% are part time (all these categories overlap a lot of course).
When you add it all up though, only about 20-25% of the working age population will be taking their car to work every single weekday.
These are useful stats to remember when certain people carry on about EVs breaking the grid when “everyone” plugs in when they get home at 6pm.
Also, there is the issue that vehicles are limited in their output. Therefore, you may not be able to run your electric house because the car can only output 5kW (or whatever) and this can’t run your induction cooktop along with your other stuff.
Whereas a multiple battery system with an appropriate setup can. I say appropriate rather than getting a hybrid inverter that suffers the same limitations as the car.
You’re referring to V2L capacities on vehicles. This relies on an AC transformation that occurs in the vehicle, from the DC battery. And the limitation is caused by that internal product.
V2G/H are generally going to be fed directly from the DC battery, where that limitation won’t exist, and the limitation will be at the external product (Bi-directional DC charger/inverter) which will easily exceed the power requirements of a standard home.
I have a 10kW solar system with 10kWh battery and would be interested in having V2G on my car to give my home system some extra storage capacity. I agree it doesn’t make sense to be completely dependent on V2G for storage but I am with Amber as my electricity retailer, and pay wholesale power prices, so additional storage would be economically worthwhile during times of high prices, which can exceed $10/kWh.
The complications you talk of wouldn’t worry me. I always leave my EV plugged in when it’s home. And if it’s not plugged in I still have enough capacity in my home battery to be able to avoid drawing from the grid. Elon Musk’s comment “If you unplug your car, your house goes dark”, like many of his comments, is rather deceptive.
Yep, I’ll be ready to try V2G when it’s available.
Spot on Finn.
We just moved home to one with no solar PV and so I have pulled the trigger on installing a new system with 14.7 kW PV, 24 kWh of storage and gateway for backup / smart management. Our EV will use our regular wall mount OCPP charger to charge at lowest cost.
Our V2L is can provide some supplementary power if ever required but that should be a pretty rare occurrence now with decent sized home battery (we get about 15 outages/year).
In my view an EV is like a hot water storage system – a strategic discretionary load which can charge when energy is cheapest to perform it’s primary job when convenient/needed.
Perhaps V2H is the answer. If the car is out so are you. I agree that soaking up excess solar with a vehicle is a no brainer.
I agree, co-ordinating vehicle charging, solar PV and grid prices should be simple.
But my actual experience has made me wonder why none of the parts of our home electrics could could communicate any hint of awarenessto the others.
Why wouldn’t an EV be able to check the grid wholesale price or the inverter output or the direction and amount of current flow through the ‘smart’ meter?
The feed in tariff is 10 cents but the usage fee is 25 cents. Why can’t the EV charger slow or pause charging when the aircon kicks on?
Hi Randy
ChargeHQ is able to do nearly if not all of that. But there is a monthly subscription fee to pay.
Hi, thank you! That is exactly what I’m looking for.
We get paid $0.15 less for solar than we pay, because the wire service provider keeps the grid usage fees
We average 500 KWh a month in the Tesla, so the app costs $7 per month and we could save up to $75 a month on the utility bill.
I can see vehicle to home being an option though
plug car in use some battery to power home in the evening when you get slugged peak price.
Maybe you only save $2-3 per night but $730 – $1095 pa
Hi Brad,
There’s a bloke featured in this article who does exactly that.
https://www.solarquotes.com.au/blog/hoem-review/
As a retired person living in the “Disaster State of QLD” V2H looks to be better financially with the associated trade-offs mentioned (certainly cheaper than installing separate batteries at current prices).
Hi AR,
You’d probably be interested in this device…
https://www.solarquotes.com.au/blog/hoem-review/
Nice article Finn. Definitely a lot of fact and reality in what you have just said.. It sounds wonderful, V2G but the practicality will be limited to (1) households who can afford to have one vehicle setup for V2L (call it your stay at home car) and your second car being your primary run around car. (2) Retirees who can afford to alter their lifestyle around their car charging. The TRUE REALITY for most family’s is that it won’t work around a busy home/work/school/activities lifestyle.
I was thinking the other way, when your battery is still good but the EV is worn out and not worth trading in, put it on blocks in the front yard and you have additional battery capacity 😉 Added benefit of keeping house prices low in your neighbourhood as well…
Seriously some EV’s are getting dangerously close to being cheap enough you could just about buy one to just use the battery for the house, cheaper than the same capacity in home batteries.
Best thing about v2g or h is its a much bigger battery as well as a car but I hear what you’re saying !!
With the election home batteries might be cheaper with a bit of luck !!
Gotta say – dont disagree with you to often Finn – but this is one. You imagine complexity, hassle and cost and for the early adopters (enthusiasts) it will be. However imagine 5 years down the track – you buy a house battery that is sized right for your house for shaving peak – but no more. (Sort of like everyone thinking you need to buy a car with 600Km range now, instead 300Km is going to cover 90% of 90% of peoples use cases.)
You plug your car in when you get home and the car and battery talk and advise each other of their SOC. The system looks at your calendar and says he only has a normal day of driving to the office tomorrow – so the car is available to help shave power overnight – announces that to the Grid Operator – who has a AMEO LOR event predicted – it sends you a text asking you to confirm if you want to participate (you have prefilled in your preferences to opt in and how you want to be rewarded – for every hour you feed in your get 20 hours of free charging credit ?
You are correct, it does make people wait.
But waiting still seems like the right thing to do when it comes to batteries, at least in areas that still have decent FITs. I got my solar system December last year and already have $300 credit built up, so big bills aren’t here yet.
When you compare the cost of home batteries to EV barriers as cost per kWh of storage.
The EV battery is 30% cheaper per kWh and comes with a free car. (60k for BYD seal 82 kWh battery)
If home batteries aren’t twice the capacity at half the cost within 5 years I’d be surprised.
Installers also seem to push buying an inverter that costs an extra $2500 just so you can add a battery later.
Or even worse, make you pay for a DLC to unlock that function later (Fronius)
If you plan to get a battery in 5 years and connect it to 5 year old technology just seems insane to me.
I put the $2500 into my mortgage and will put it towards a battery with an integrated inverter system in 5 years time.
I don’t understand people quoting stuff like “EV batteries are 30% cheaper than home batteries.”
AlphaESS SMILE5 13kWh is about $8500. $650/kWh
BYD Seal Premium 82kWh from $52990. $646/kWh
Where is the 30%?
You could argue that AlphaESS isn’t premium, that its warranty isn’t good enough, that there isn’t a fixed AUS retail price,
but the BYD Seal is also a newish product that people don’t necessarily trust!
Hi Nigel,
Just look up the reviews of alpha and the warranty support… it’s junk.
Maybe*, but I am pricing Apples against Apples.
Folk who compare a _premium_ Tesla PowerWall against a _budget_ GWM Ora/Chery Omoda/MG ZS are comparing Apples with Oranges, and can easily see a 30% home battery+inverter premium.
Try a Tesla Powerwall against a Mercedes EQC and see which way the price per kWh goes?
(* I have installed an old B3, and a SMILE 5. Had DOA battery replaced on the latter. Generally been happy with AlphaESS support)
While the 30% cheaper wasn’t really the main point, (That batteries will still come down in price was)
Aren’t BYD has the best batteries for EV? AFAIK with the Blade and upcoming Blade2 are supirior to anything else on the market?
So Comparing Apples to Apples
BYD Seal Premium 82kWh from $52990 = $646/kWh + Free Car
BYD 13.8 kWh Home battery $11490 = $832/kWh
So 22% cheaper and a free car.
But lets look as close together as we can with the cheapest car and the biggest battery
BYD Dolphin Essential $30,000 / 44.9kWh = $668 + Car
2x BYD 19.3 Kwh Batteries $30,980 / 38.6 = $802.59
I also accept that you should be able to get a better deal on home batteries than advertised online if you are buying 40-80KWH worth but its still cheaper to buy them with a free car included.
I hope they do get 50% cheaper in 5 years time !
(both EV cars _and_ home battery ESS)
…but I suspect the economies of scale will always favor the cars being cheaper. Many more cars sold than Australian certified home batteries.
And if you bring V2G/V2H into it, doesn’t that muddy the waters even further?
What auto manufacturers are going to do the engineering to make that compatible, and a selling point?
If battery production targeting Australian home solar is niche, how much more so batteries in EVs that are also warranted for heavy V2G/V2H?
P.S. Agree completely with the craziness of buying a Hybrid inverter “just in case” in 5 years time you might buy/install a battery that is still compatible with it.
P.P.S. BYD 24kWh $16,699 ? https://solarsuperstore.com.au/collections/byd-lvs
OK. self-interest is a primary concern, especially when wage slaves are being done over – cost containment is essential. But QLD floods remind us that cutting CO₂ is vital too. Even off-grid here, 42.5 kWh of photons into the EV & HWS two days ago, at least 35 kWh going in today, and 25 kWh on a grey day, so it’s the *Panels* & serious inverters ya want! Overdo the *Panels*
fourfold, with inverters to cope.
With 46.5 kWh of batteries, V2H is not needed here, despite 3 aircons & 2 fridges, EV, etc. And V2G’s lunch will be eaten by gridscale batteries at ¼ our price. Their instantaneous output will devour any spot demand, leaving nothing for crumb merchants.
However, at 2150 kWh AC input for 10,000 km, my MG4 has saved .465*$1.82 = 84.6c/kWh.
Not a bad FiT for off-grid, eh?
That’s after-tax $, too. Your money, not pre-tax illusion.
And the EV is soooo much better to drive. I wonder if there’s a runout offer coming?
(But the new model is ugly in comparison.)
What a load of rubbish!
$35K NISSAN LEAF is the cheapest battery you can get without the hassle of vetting installers, signing forms for gov. rebates etc.
Whether its V2L or V2G it makes perfect economic sense!
Be creative and tax-deduct + depreciate all you like to your IP and/or ABN.
FBT exemption – extra cash!
Think outside of the box: get your 0% balance transfer credit card to get pre-tax dollars credit to pay for it altogether and pay it back in 24 months – beat the dealer best offer by far!
NPV wise, best bang for your buck
Yes it requires a different set up but all worth it at the end.
For some time I’ve been thinking an EV with a decent range / kwh of battery would be in the $70-$80k price range now, and yes you’d be wise to have a long range EV so you can juggle times you want a decent trip, and say winter type solar / home needs.
And from there, why depreciate the battery in an expensive EV more than it’s already subject to, when $10k will get you the battery capacity you need for most home non solar use ?
You can get a buzz box EV for around town, and soak up all the excess production to both battery and vehicle as needed . . . in dead of winter, you can charge either up as best suited frm cheapest time of day tariff.
Everything is fine until the sun goes down. We had so much rain in Queensland so 20 KW Solar and 50 KW battery lasted for 3 days…then the grid kicks in..thanks God!
First the cyclone hit from the east, then tropical low came from the North and now the Ex Cyclone Diane from the West.
So off grid is not an option..Yes, is good to have battery but in situation like this year makes wonder was it worthy the investment?
Cyclone Alfred gave us a 6 day blackout. My 20 kWh of batteries helped a little, but the sun wasn’t shining to top them up. So out with the trusty gennies and the 18 extension chords. Septic, water, fridges, freezers, internet, PC’s – there is a lot to plug in. Just the setup was a hassle, let alone the 2am alarms to refil the tanks. I dont know how much a bi-directional charger will cost, but i would have loved the extra 88kWh sitting in the car that wasn’t going anywhere. Like some of the others who commented, we get a lot of outages and V2H would provide a lot more flexability. No sure about V2G yet – hopefully it wont be long before we can comment from experience.
V2G will have it’s place, at least as a battery refill. I see it as being plan B when plan A fails. With V2G you can totally go off-grid with a relatively small battery. If the sun doesn’t shine for few days, or your panels develop a fault and your battery starts to run out of power. Then all you do is a quick trip to the community charge point, fill up your car battery, return home and charge up your home battery. It would be quite rare you have to do this, but you have comfort knowing that you can do this, alleviating anxiety.
V2G isn’t about selling to the grid, it is about removing the grid.
I think you’re talking about V2H?
I believe Finn is referring to V2G which is having your bidirectional charger linked to the wholesale price of electricity, and using it to export when electricity is expensive and import when it’s cheap.
V2H on the other hand is a no-brainer.
Here’s another factoid. The new Volkswagen EVs on sale in Australia do support V2G… But read the “fine print” on https://www.volkswagen-newsroom.com/en/press-releases/cleverly-manage-your-own-electricity-first-id-models-support-bidirectional-charging-17949
“02. The discharging and bidirectional charging functions are no longer available once the intended operating time or energy quantity has been reached: Max energy quantities: Up to 10,000 kWh Discharging; Max operating hours: Up to 4,000 hours Discharging”
That’s not high. If you sold your energy at 30c/kWh, you’d make $3,000 before you hit your 10,000 lifetime limit. That wouldn’t pay for the bidirectional charger.
Maybe Volkswagen is being excessively conservative here?
I disagree. I think a small <10kWh battery at home and a V2H/V2G EV maximises use of battery resources. The tech and standards are already here in Oz so why not support it? It's only software and an inverter at the end of the day…
Ozzies have one if the largest carbon footprints per person of any population, so yes the sooner we move to EVs the better. But I think the financial incentive of V2H will be a catalyst in changing behaviour to charge EVs during the day (max solar) and reduce the morning evening grid duck curve using V2H.
The big wind farms are going to change it up a bit; and there are days with no wind and sun, so I understand the push for V2G by authorities.
Great post, Finn. I agree—V2H/V2G is too complex, inconvenient, and pricey. I’ve got a 10.8 kW solar system with an 8.2 kW inverter on the Gold Coast for 6 years. It hits 8.2 kW on warm days, but my bill’s never in credit. I work from home with a 3-phase, 18 kW AC running 12 hrs/day half the year, plus a Tesla Model 3. I export ~14 kW daily, likely when the AC’s compressor eases off. I suspect one phase feeds the AC, so excess solar gets exported, not used. A battery could store that for night use (AC, kitchen), but V2H/V2G with the Tesla? Too much hassle, as you said.
Billing in Australia is all net billing.
So -10kW on phase 1, +5kW on p2, +5kW on p3 (for an hour) is viewed as 0kWh for your electrical bill. You don’t pay for 10kWh and then get FiT for 10kWh.
The way I view it is like this:
Energy independence is something people aim for.
The two things you need is a lot of generation (panels on your roof) and excess storage.
For 75% of the year (or more, depending on location) your 10-15kWh home storage system will get you by each night.
But for prolonged outages and/or inclement weather, you really need extra storage.
EVs with bidirectional charging offer you that extra storage, without needing to pay for the exorbitant amounts of storage that you need for the small amount of the time that you need it.
They work hand in hand with the extra storage requirements, while still being a functionally useful car the rest of the time.
After re-reading your article Finn, I think I’ve (along with a few other responders) misunderstood your post.
You’re (i think?) specifically talking about V2G capabilities, that being feeding into the grid when the price is right, and other services like FCAS, etc.
I agree V2G orchestration is definitely years/decades away from becoming a reality (if ever). I imagine it would need a great collaboration between a hardware vendor and a retailer (which I believe Amber are starting that process).
So, trying to bring my response from above in line with the actual purpose of your article – yes V2G is likely to be a long way away and nobody should be waiting out for battery installations in the hopes of V2G becoming a reality soon.
Bidirectional chargers and V2H however, are definitely an exciting progression and supplement to small sized home batteries, for early adopters in the next twelve months or so. V2H allows the customer to put a smaller sized home battery on, which is a benefit
10 grand for a 10kWh battery is the problem.
Here’s an actual solution instead of this V2X crap: portable batteries for the CAR and HOME.
If power tool companies can make 1 battery fit all their tools, car makers can make battery modules that go from CAR to HOME STORAGE just as easily.
Eg: You can leave up to 60% of your car’s battery modules in the home charger (40kWh) permanently because you’ll rarely need to use all 60kWh in your daily commute, nor is it a good idea to carry all that unnecessary weight around. So, they stay at home permanently soaking up all the solar power during the day so you won’t have to spend money on an OVERSIZED solar system only to then export the excess for pittance. Those battery modules are going to power your home on a permanent basis and at a time the sun has gone, when you’ll actually be at home and need power. No more having to make sure all your appliances run during daylight hours to utilise solar power.
Have a look at the Gogoro swapping system – it could do exactly this – although the batteries are comparitively quite small – about 2.5Kwh each – and to make them easy and convenient to swap you would really need them to be up at about waist height – so that will affect the centre of balance of the car. But it is also a way to let people easily sell their solar power – they give you a charging station at home and each time you fill a battery you can drop it off for credits at the local swap centre
What would be better is a small “starter” car for city kids – one of the micro EVs that took a few of these batteries and was speed limited – make it under license here in australia and mandate it for new P plate drivers (with exemptions for Tradesmen etc)
Craig
Some key points that challenge your idea.
1. Different charge states for car battery cells are problematic eg ones used in house vs in car. I don’t know if this is solvable. Many other battery management issues would also arise both in car and home.
2. In modern EVs, the battery is often a structural element of the car. How would the structural integrity be maintained without key parts? Car structures are subject to high loads.
3. Battery components are heavy and voltage/current issues risky for those not skilled with the right equipment. How would you remove/replace components safely and easily?
4. Cost – high and demand questionable.
5. Do your Ryobi batteries fit my AEG tools? No. Nor any other brands as far as I know. Why? Various reasons. The fact Ryobi batteries fit many Ryobi tools is irrelevant to your concept.
People would love batteries in EVs to be simply swappable between models and brands, they aren’t and won’t be. Car engines aren’t in 130 years of use.
Thai, the devil is in the detail, unfortunately. Earlier BEV batteries were 400 Vdc, now they’re often 800 – 1000 Vdc, for very high power charging at currents which do not melt even heavy cables.
House batteries, on the other hand, are most often 48 Vdc, one or two at 72 or 120 Vdc. Not even those can be mixed. The battery inverter/charger associated with each of those batteries is seriously incompatible with any of the others – a loud bang and smoke/fire would usually result. (Even more exciting with BEV voltages. 😉
Rather than fume over incompatibility between AA cells for my radio, and cordless tool battery packs, I accept that a screwdriver is not a hammer, though both are tools. Application-optimised design is central to engineering, due to the superior results. Mass production exacerbates the trend, unavoidably.
In Victoria, an interest-free loan on the 70% battery cost you’d pay for yourself yields savings now. It works.
Thank you, Finn. Another easy to understand and well explained article.
Much appreciated.
But Finn home battery prices aren’t going down….
Companies are trying to drum up business with hysteria about feed-in-tariffs dropping. They don’t want bi-directional charging to be viable because then they lose a big slice of market opportunity. A car battery is 4 to 8 times bigger than a single 11kW PW3 that costs $16K plus to buy and install. Until companies stop trying to gouge consumers with massively marked-up home batteries the ROI is still not there. Do the sums and see through the sales pitch and spin.
The EV company that partners with a reputable bi-directional charging provider and gets after viable V2H (less complex to make happen than V2G) will dominate the market and leave all those other brands in their dust.
I think it’s the economics, not the “companies”
Yes, V2H for emergencies, but not to add cycles to EV batteries. It’ll likely always be cheaper per KWh to build and commission a SEACAN sized batrery pack.
And smart charging. I think it’ll always make the best economic sense to use electricity from the car battery only for operating the car.
That’s my perspective from here in Canada. We had our last multiday outage in 1986 from an ice storm, and any natural disaster we have like tornado or fire leaves nothing behind that needs electricity or has solar panels on top.
This national broadcaster story asserts that a mere 6 kWh of battery allows 91% of consumers to time-shift most of their evening shoulder consumption off the loaded grid onto free midday photons:
https://www.abc.net.au/news/2025-04-06/the-battery-subsidy-and-all-you-need-to-know-for-your-household/105138430
OK, a hard % on a rubbery outcome is bunkum, unless they’re claiming the other 9% cannot have batteries at all. (It’s a case of “Pick your model, never mind reality.”, I figure.)
Nevertheless, with part subsidised, part interest-free loan in Victoria, it’s a cheap way to help keep the grid up in trying times, and a personal boost when it goes down. That’s an economical social good.
At $2700 for a 5 kWh box with BMS, buy two, add a 5 kW battery inverter for whole-night autonomy in grid outages. Sparky installs, with grid-disconnect switch. Generator input on the battery inverter extends household crisis uptime. No emergency midnight icecream eating session needed.
I rarely disagree, but…
Home battery prices haven’t fallen significantly in the past decade, yet EV prices have. By the time they do, V2G will have had a chance to go mainstream.
Elon Musk has an obvious conflict of interest because his company sells separate home batteries and EVs. He has shown just how corrupt he is in recent times, buying an election and using it to prop up his own business interests.
Presumably, SolarQuotes also has a conflict of interest with wanting people to buy separate home batteries. But why not support all relevant technologies by getting involved with selling EV chargers, V2G or otherwise?
“Just like solar panels, prices will fall and home batteries will be everywhere.”
“So don’t wait. …Use what works — now.”
So, are we waiting or not waiting? And who says that V2G won’t form a part of the prodigious quantity of energy storage that will be needed in order for society to phase out coal power?
I wouldn’t trust Musk as far as I could throw him. He will go down as one of the biggest conmen in modern history. Tesla is a meme stock mostly based on his lies and exaggerations. FSD next year for a decade. Just recently, a ‘legion’ of Optimus robits for sale later this year and 10 legions next year, when only 5-6 months ago they couldn’t even demo the thing wihout being remotely controlled by humans. Fake solar roofs demoed. Doctored FSD videos with pre-planned routes. The $40k Cybertruck with a 550-mile range. The nationwide network of soloar powered gigachargers for the Semi with electircity gyranteed at 7c/kWh. The Roadster II “in production now” over 7 years ago and $250 million in deposits taken. A million Cybertaxis on the road by 2020. Several years agoi, you’d be insane not to by a Tesla becuase you’ll soon be able to make tens of thousands each year putting it to work as a cybertaxi. .
He is a conman.
Maybe Elon is a bit of that, but he’s always stuck to hydrogen fuel as a lost cause, and V2G as a worthless / pointless thing that we can do, but needn’t / shouldn’t.
The Tesla vehicle website can display fuel “savings” calculated as fuel alternative at 25 MPG and the current market price, versus electricity at free.
V2G is kind of the same. It requires that you pretend that:
– you’re not going to “use up” any battery life, that
– the bidirectional charger costs next to nothing, that
– the utility will buy electricity at a high price, from tens of thousands of customers, often enough to pay for the extra hardware ( rather than buying one or two big batteries) and that
– the car companies will just eat the extra warranty cost.
None of which I believe.
But V2L or V2H, sure. I’d like to use an electric grille when camping, rather than carry the propane bottles.
Quite frankly Finn, I think this is the first article on SQ that expresses the opinions of the Origin overlords rather than actual science.
As Arena stated in their EV charging roadmap, if just 10% of the 1.5 million EVs expected to be on the road by 2030 participated in v2g, it would account for 37% of the NEMs storage requirements. That is going to seriously disrupt the AGL/Origin duopoly.
As far as some of your arguments:
It’s expensive. Yes so was solar, for what I paid for a 1kw solar system in 2008 I was able to install a 10kw system in 2020. It’ll get cheaper.
It’s fiddly. Maybe, but if you look at some systems like the Sigenergy setup that you showed a couple of months ago, systems are becoming more integrated and simpler. You can even have a small battery on this system to cover when the car isn’t home.
V2G may well be the elixir tat finally lowers over inflated energy prices, time will tell
But will the car makers go along with V2G? Have any of them clearly stated what their warranty policy will be? (Other than Tesla’s Just Say No)?
V2G seems to be an idea that economics is standing back awau from, and ready to crush.
I would wager yes they will jump on it and very shortly. We are about to be hit with a tsunami of new name brand chinese EVs this year (and probably more than originally expected because of the Trump Tarriffs) – they are going to have to find something other than price to differentiate themselves in the market – i think that will be V2G. Once they start doing so too will the likes of BYD – remember BYD are talking about million mile batteries already – and everyone knows that the use of batteries for V2G is far kinder on the batteries than they experience under normal driving conditions.
I just don’t see anything to indicate that V2G is coming to our electricity market. There’s no regulation or desire for the grid operator to pay extra for the electricity during peak load – in fact we’re specifically only allowed to get paid back, what we paid. You couldn’t possibly get paid more dollars than the electricity cost you to get.
I’ll believe in V2G here when I see the auto makers and the grid operator (AESO, Government agency) making it at least possible.
They seem to be running some large trials in China, but I think the one V2G capable charger available in Australia is discontinued, and there never was one certified for Canada. I have seen youtubes of V2G setups in the UK, along with small wind turbines and solar.
You obviously haven’t been paying attention. Australia released their v2g standards late last year and there are already bidirectional charges available although, as far as I am aware, not yet approved by the CEC so they can’t be installed on the grid.
Nobody is going to pay extra for the power, the owners of v2g setups would join a retailer like Amber where wholesale energy price is exposed to the end user so they fill their car up during the day when the wholesale price is low (lots of sun, not much demand) and feed it back in the evening when the wholesale price is high (lots of demand but no sun).
On top of this you’re bringing supply closer to the consumer so less need for expensive transmission and also the DNSPs won’t need to spend as much to re-engineer their networks to cater for times of so much extra supply than there is demand. It should in theory mean cheaper prices for everyone.
Don’t uou find that V2G is so often “damned with faint praise”?
For a decade, we’ve had millions of large EV batteries around the worls that just sit parked over 90% of the time, while commitees and boards squabble about standards and certifications
Meanwhile, how mamy grid connected solar inverters, home batteries, etc are on the market, almost everywhere?
The Australian electricity market seems one of the most advanced, globally, ot’s had more grid inverter connected solar for longer, than anywhere exc. maybe Germany or California.
Maybe Aus will be the first to get V2G past the 20 car limited fleet trial stage. But it just seems to never quite caych fire and get going. Neither the carmakers or the utility stand to benefit,, maybe?
I love the irreverent tone of the article 🙂 Refreshing. I do think though that V2G is inevitable if we are to cost effectively address the way the grid will work in the future.
The guys over at reneweconomy might take you on with some of your thoughts. The key is the ubiquitous opportunity to plug in when the car is not in use, home, work, shops, where ever and very smart software to manage loadss, charging discharging etc. I think the curtailment of renewables last year was equivalent to the (eventual) capacity of Snowy 2.0! That could be going into EV’s and/or green hydrogen imho.
I think the solution will be a small home battery (~10KWh) and V2G as the grid will need storage close to load.
I do agree there is a lot of red tape to cut, but the benefits will be worth it.
In terms of the money, I think if the system is through something like Amber, accessing the wholesale market could change things, although who knows what that will look like once fossils are out of the picture.
My first reaction to V2G enthusiasm is that the proposed $2.3B domestic battery subsidy, multiplied by 3 = $6.9B of fixed always-available batteries, which has been stated to exceed the capacity of Dutton’s seven imaginary nuclear power plants – at a few % of the cost, perhaps. (Even without wind, solar is on a trajectory to exceed grid demand in reasonable time.) So will V2G be needed, long term?
But I’ve read here that many cars are not daily commuters, and other drivers are retired or WFH, providing a massive collective grid buffer not to be ignored.
There can never be too much storage, not least when an increasingly energetic atmosphere repeatedly clobbers above-ground transmission.
And, well, once we have it, we’ll use it. Energy surplus allows cheaper goods, locally made – no bad thing if trade wars proliferate.
The network providers will suck out all the profit they can, though. The remaining benefit might just be blackout resilience + a cup of coffee?
At this moment, we already can have EV’s with V2L and mostly with a car inverter working already at 3.6KW output. There is already a software-hardware solution in Germany that simulates the behavior of solar panels for an inverter during MPP tracking (the communication between inverter and solar panels). This means that any 230V power source can be integrated into an existing solar system via the solar module input on the inverter. This could be, in particular, electric vehicles with V2L function, mobile batteries or propane, petrol and diesel generators.
So, this simple system is placed in between existing PV panel setup and your existing home inverter and can be controlled and limited with a smarphone. Because nothing change after your home inverter, the system is completely legal and put in between by disconnect and reconnect via MC4 connectors. Power will continue flow to your home- or battery or grid as setup in the app. Do you still need V2G then ?
Hi Francis,
I’d be fascinated to see this 230vac to “DC solar” output device if you have a link to share please?